A private development company needed a stormwater wetland solution for a residential subdivision. The purpose of the stormwater wetland was to treat runoff pollutants and provide protection for a sensitive SEPP 14 natural wetland located immediately downstream from the development.
The main challenges included:
- Variable flows and water quality
- Lots of fine clays in the soils
- Protection of sensitive ecosystem
- Community concerns about mosquitoes, safety for children, flora and fauna
Keith Bolton and David Pont were engaged to design a stormwater treatment wetland and to manage community consultation. The system was designed with a number of treatment functions to address both particulate and dissolved pollutants, through the use of inlet zones, gravel beds with melaleuca trees, and incorporating open water zones.
The use of gravel beds and dense plantings in macrophyte zones formed the core of the system, as this combination has provided excellent performance.
The wetlands have now been in operation since about 2005 and continue in excellent condition. The constructed wetlands host several attractive plant species mainly in the shallow water (public safety advantage) as well as supporting a prime habitat for birds and frogs. Brolgas have been regular visitors.
The wetland treatment system continues to produce clear water, and has become an integrated part of the local community, being frequently used as a recreational asset by walkers. A key result has been the large numbers of frogs in the wetlands, and the way in which the wetlands have grown as part of the beautiful natural environment of the site.